1. PowerPoint ® Lecture Slide Presentation prepared by Dr. Kathleen A. Ireland, Biology Instructor, Seabury Hall, Maui, Hawaii The Chemical Level of Organization

2. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Learning Objectives Describe an atom and compare the ways atoms combine to form molecules. Distinguish among the types of chemical reactions that are important to physiology. Describe the role of enzymes in metabolism. Distinguish between organic and inorganic compounds. Explain the importance of water, pH and buffers to living systems. Discuss the structures and functions of carbohydrates, lipids, proteins, nucleic acids and high energy compounds.

3. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings SECTION 2-1 Atoms, Molecules and Bonds

4. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Subatomic particles Protons = positive charge; weight of approximately 1 Dalton Neutrons = no charge; weight similar to protons Electrons = negative charge; weigh 1/1836 th Dalton Protons and neutrons are found in the nucleus; electrons occupy electron cloud Atomic number = proton number; atomic mass = protons and neutrons Isotopes are elements with similar numbers of protons but different numbers of neutron Atoms are the smallest stable units of matter

5. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 2.1 Hydrogen Atoms Figure 2.1

6. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings The outermost electron shell determines the reactivity of the element. Electrons occupy a series of energy levels or electron shells.

7. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 2.2 Atoms and Energy Levels Figure 2.2

8. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Molecule = a chemical structure consisting of molecules held together by covalent bonds Compound = a chemical substance composed of atoms of two or more elements There are three types of bond: Ionic, covalent, and hydrogen Ionic = attraction between positive cations and negative anions Atoms combine through chemical reactions

9. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 2.3 Ionic Bonding Animation: Formation of Ions PLAY Figure 2.3

10. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Double covalent bond Non-polar covalent bond Polar covalent bond Covalent bonds exist between atoms that share electrons to form a molecule Figure 2.4a, b

11. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Polar covalent bonds that occur when hydrogen covalently bonds with another element Hydrogen bonds are weak forces that affect the shape and properties of compounds

12. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 2.5 Figure 2.5 Polar Covalent Bonds and the Structure of Water

13. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 2.6 Figure 2.6 Hydrogen Bonds

14. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Matter can exist as a solid, liquid or gas Depends on the interaction of the component atoms or molecules Molecular weight is the sum of the atomic weights of the component atoms Chemical notation Short-hand that describes chemical compounds and reactions See table 2.2 for examples of chemical notation Matter and chemical notation

15. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings SECTION 2-2 Chemical Reactions

16. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings All chemical reactions in the body constitutes metabolism Metabolism provides for the capture, storage and release of energy A chemical reaction occurs when reactants combine to generate one or more products

17. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Work = movement of an object or change in its physical structure Energy = the capacity to perform work Kinetic energy is energy of motion Potential energy is stored energy resulting from position or structure Conversions are not 100% efficient, resulting in release of heat Basic energy concepts

18. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Types of reaction Decomposition Synthesis Exchange Metabolism is the sum of all reactions Through catabolism cells gain energy (break down of complex molecules) Anabolism uses energy (synthesis of new molecules) Metabolism

19. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings All reactions are theoretically reversible At equilibrium the rates of two opposing reactions are in balance Anabolism = catabolism Reversible reactions

20. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Activation energy is the amount of energy needed to begin a reaction Enzymes are catalysts Reduce energy of activation without being permanently changed or used up Promote chemical reactions Enzymes, energy and chemical reactions

21. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 2.7 Enzymes and Activation Energy Figure 2.7

22. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings SECTION 2-3 Inorganic Compounds

23. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Nutrients are essential chemical compounds obtained from the diet Metabolites are molecules synthesized or broken down inside the body These can be classified as organic or inorganic compounds Organic compounds have carbon and hydrogen as their primary structural component Inorganic compounds are not primarily carbon and hydrogen Nutrients and Metabolites

24. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Water is the most important constituent of the body Solution is a uniform mixture of two or more substances Solvent is the medium in which molecules of solute are dispersed Water is the solvent in aqueous solutions Water and its properties

25. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 2.8 Water molecules and solutions Figure 2.8

26. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Compounds that interact readily with water are hydrophilic Compounds that do not interact with water are hydrophobic Electrolytes undergo ionization

27. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Neutral Acidic Basic pH is a measure of the concentration of hydrogen ions solution

28. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Acids release hydrogen ions into solution Bases remove hydrogen ions from solution Strong acids and strong bases ionize completely Weak acids and weak bases do not ionize Acids and Bases

29. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 2.9 pH and Hydrogen Ion Concentration Figure 2.9

30. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Salt = an electrolyte whose cation is not hydrogen and whose anion is not hydroxide Buffers remove or replace hydrogen ions in solution Buffer systems maintain the pH of body fluids Salts and buffers

31. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings SECTION 2-4 Organic Compounds

32. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Organic compounds generally include Carbon Hydrogen and sometimes Oxygen Organic compounds

33. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Four major classes of organic compounds are Carbohydrates Lipids Proteins Nucleic acids High energy compounds are also organic compounds Organic compounds

34. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Important energy source for metabolism Monosaccharides, disaccharides and polysaccharides Di- and polysaccharides formed from monosaccharides by dehydration synthesis Carbohydrates Figure 2.10c

35. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Animation: The formation and breakdown of complex sugars PLAY Figure 2.11 The Formation and Breakdown of Complex Sugars Figure 2.11

36. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 2.12 The Structure of a Polysaccharide Figure 2.12

37. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Five classes: Fatty acids Eicosanoids Glycerides Steroids Phospholipids Glycolipids Lipids include fats, oils, and waxes

38. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 2.13 Fatty acids Figure 2.13

39. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Triglycerides = three fatty acids attached by dehydration synthesis to one molecule of glycerol Figure 2.15 Triglyceride Formation Figure 2.15

40. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Are involved in cell membrane structure Include sex hormones and hormones regulating metabolism Are important in lipid digestion Steroids

41. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 2.16 Steroids Figure 2.16

42. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Structural proteins Contractile proteins Transport proteins Enzymes Buffering proteins Antibodies Proteins perform many vital functions in the body. The six important types are:

43. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Amino acids contain an amino group, a carboxylic group and a radical group Polypeptides are linear sequences of amino acids held together by peptide bonds Proteins are chains of amino acids

44. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 2.18 Amino Acids Figure 2.18

45. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 2.19 Peptide Bonds Figure 2.19

46. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Primary structure (amino acids sequence) Secondary structure (amino acid interactions) Tertiary structure (complex folding) Quaternary structure (protein complexes) The four levels of protein structure are:

47. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 2.20 Protein Structure Figure 2.20

48. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Reactants (substrate) interact to yield a product by binding to the active site of the enzyme Cofactors must bond to the enzyme before substrate binding can occur Coenzymes are organic cofactors commonly derived from vitamins Enzyme reactions

49. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 2.21 A simplified view of enzyme structure and function Figure 2.21 Animation: Enzyme structure and function PLAY

50. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Proteins pushed outside their optimal temperature and pH range become temporarily or permanently denatured and will cease to function The shape of a protein determines its function

51. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Store and process information at the molecular level Made of purines and pyrimidines DNA and RNA Nucleic acids

52. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 2.22 Purines and Pyrimidines Figure 2.22

53. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 2.23 Nucleic Acids: RNA and DNA Figure 2.23

54. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Nucleotides are composed of a sugar, a phosphate and a nitrogenous base Sugar = deoxyribose (DNA) or ribose (RNA) DNA Bases = adenine, thymine, cytosine, guanine RNA bases = adenine, uracil, cytosine, guanine Nucleic acids are chains of nucleotides

55. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Adenosine triphosphate (ATP) Made by adding a phosphate group to adenosine diphosphate (ADP) Process referred to as phosphorylation High energy compounds store cellular energy in high energy bonds

56. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings SECTION 2-5 Chemicals and Cells

57. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Metabolic turnover allows cells to change and to adapt to changes in their environment Biochemical compounds form functional units called cells

58. Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Atoms and how they combine to form compounds. Chemical reactions and enzymes. Organic and inorganic compounds. Water, pH, and buffers. The structure and function of carbohydrates, lipids, proteins, nucleic acids and high energy compounds. You should now be familiar with: